PET-CT offers accurate assessment of tumour length in oesophageal malignancy

Abstract

Introduction: Radiotherapy is increasingly used for both curative and palliative treatment of oesophageal malignancy. Accurate treatment depends on determining tumour location and length. This study assessed the value of PET-CT versus other staging modalities in determining tumour length.

Materials and methods: Oesophageal cancer patients who underwent staging with PET/CT and endoscopic ultrasound (EUS) in addition to their diagnostic upper GI endoscopy and subsequent surgical resection were assessed. PET/CT length was obtained retrospectively by using Hermes Hybrid Viewer™ with a 1-5 Standardised Uptake Value grey scale. An SUV of 5 was used as the cut off for determining length. Direct measurement by EUS and OGD were determined.

Results: 53 patients underwent PET-CT, EUS, OGD and surgical resection for oesophageal cancer. Overall the correlation between PET-CT and histopathological length was strongest (Pearson r=0.5977, 95% CI 0.390-0.747) versus EUS (Pearson R=0.5365, 95% CI 0.311-0.705) and OGD (Pearson r=0.1574, 95% CI -0.118 to 0.410). After excluding tumours with a significant chemotherapy response, PET-CT length correlated significantly with histopathological length (R=0.5651, p=0.0005). In comparison, the correlation between histological length and EUS (R=0.4637, p=0.0057) measurement was less significant and this did not correlate with OGD (R=-0.1084, p=0.5417).

Conclusion: Tumour length estimated by PET-CT correlated most strongly with histopathological length of oesophageal malignancy and is the most accurate determinant of tumour length of all the staging modalities. This suggests a potential role for PET-CT in the planning of radiotherapy and resection, particularly when considering the practical limitations of EUS.

Keywords: Endoscopic ultrasound; Oesophageal malignancy; Oesophago-gastroduodenoscopy; PET/CT; Tumour length.